U.S. Pat. No. 4,978,816 entitled "Circuit Breaker Handle Interlock Arrangement" describes an interlock feature that prevents the circuit breaker handle from being padlocked when the circuit breaker handle is in its ON position.
U.S. Patent application Ser. No. (41PR-6786) entitled "Circuit Breaker Contacts Condition Indicator" describes a combined auxiliary switch and contacts indicator accessory that allows visual verification of the OPEN and CLOSED conditions of the circuit breaker contacts.
U.S. Pat. No. 4,982,173 entitled "Rotatable Trip Test Assembly for Molded Case Circuit Breakers" describes an externally-accessible trip-test button that is pressed to articulate the circuit breaker operating mechanism for test purposes.
All of the aforementioned U.S. Patents and Patent application are incorporated herein and should be reviewed to determine the advanced state of the art of circuit breaker technology.
When such circuit breakers are used within an industrial power delivery system to protect electrical equipment some means must be employed to insure that the circuit breakers are not inadvertently turned on when work is being undertaken on the associated equipment. Further means are required to insure that the circuit breaker contacts are in their OFF condition when the circuit breaker is padlocked to prevent access to the circuit breaker operating handle.
Accordingly, the present invention proposes a safety interlock that operates to automatically articulate the circuit breaker operating mechanism to insure that the contacts are in their OPEN condition while simultaneously preventing the circuit breaker from being interlocked when the circuit breaker contacts are in their CLOSED condition.